Exterior beam-to-column bolted connections between GFRP I-shaped pultruded profiles using stainless steel cleats, Part 2: Prediction of initial stiffness and strength

The present work focuses on the prediction of initial stiffness and strength of bolted beam-to-column connections between pultruded glass fibre reinforced polymer (GFRP) profiles using stainless steel cleats — the first part (Martins et al., 2021) of this two-part paper presented an experimental study on the monotonic and cyclic behaviour of beam-to-column connections, while this second part focuses only on the monotonic behaviour of the reinforced connections. The initial stiffness was predicted using both analytical – via an adapted “component method” – and numerical models. The stiffness predictions compared well with experimental results. This study also identified the components with the highest influence on the connections’ stiffness, namely (i) the bending of the flange cleats and (ii) the transverse compression and shear of the columns’ webs. The strength of the reinforced connection series was predicted using a mixed analytical–numerical approach, as the local failure strengths were calculated in accordance with design standard recommendations, while the load distribution per connection component was computed through finite element (FE) models. The predicted failure modes and corresponding ultimate loads were in good agreement with the experimental tests. The proposed analytical and numerical models proved to be a viable tool for the design of GFRP structures, providing accurate predictions of the initial stiffness and strength of cleated connections.